The growing demand for new hairstyles has shaped a lucrative industry for salons and hair stylists. Further, the ability to change the appearance of one's hair through chemical processes is important to both men and women. More specifically, it is important for both men and women to be able to chemically relax or to permanently wave the hair so that they may keep up with the rapidly changing hair style fashion in the hair industry. In some instances, such chemical processes, and alkali hair relaxers in particular, have the undesirable and very noticeable effect of discoloring of the natural underlying color of hair, particularly naturally blonde and gray hair. In addition, environmental effects, such as exposure to sun or smoke and like pollutants, may also cause discolorations. Also, in many individuals, the natural color of the hair may discolor with age or illness and develop an undesirable tone even without chemical processing or environmental exposure.
In general, the discoloration of natural gray and natural blonde hair due to natural processes, environmental exposure, and chemical alkaline waving or relaxing processes is a visually observable undesirable yellowish tone on the white unpigmented fibers, although other tonal alterations are observed, such as brassiness. Discolored hair fibers also appear dull, drab and lackluster, whereas in non-discolored hair, the natural underlying tone of the hair fibers provides a desirable natural bright tone with highlights to the hair. For purposes of this invention, the term "discolorations" and grammatical variations thereof with reference to hair means discolorations such as described herein including, but not limited to, yellow, brown, blue and purple tones, brassiness and dullness.
Alkali hair relaxing compositions may employ strongly alkaline relaxing agents such as inorganic alkali metal hydroxides such as, but not limited to, sodium hydroxide, potassium hydroxide, lithium hydroxide, and calcium hydroxide or oxides thereof capable of forming hydroxides in water; or relatively strong organic bases such as, but not limited to, guanidine, guanidine hydroxide or quaternary ammonium hydroxide. These chemicals are highly caustic with a pH of above approximately 12, and at such high alkalinity alkali relaxers may undesirably alter and discolor the natural tone of human hair, especially noticeable on naturally white hair fibers. Other non-alkaline relaxing compositions may also cause discoloration of the hair.
Alkali hair relaxers containing sodium hydroxide are especially popular and are commonly known as lye-type relaxers. Some lye-type hair relaxers have included keratin-disulfide reducing agents in an attempt to limit the amount of discoloration that occurs during alkali relaxing. For example, compositions with available sulfhydyrol groups, such as dimercaptoadipic acid or cysteine, have been included in the relaxer creme. However, these products do not work as well as needed and are thus limited in use, for example, as part of a relaxing process.
Waving compositions effect a substantially lasting transformation of straight hair into waved hair. Often, such waving systems utilize reducing agents comprised of thiols, including, but not limited to, thioglycolic acid, thiolactic acid, cysteine, thioglycerol, thioglycolic hydroxide, thioglycolamide and glycerol monothioglycolate. These waving composition are alkaline and typically have a high pH above 8 to about 10. Such alkaline waving compositions also may undesireably alter and discolor the natural tone of human hair. In addition, non-thiol waving compositions may also cause discoloration of the hair.
Thus, there is a need and desire for a composition and process to brighten the tone of alkali relaxed and waved hair which has become discolored to restore a more natural appearance. One commercially available hair brightening system uses hydrogen peroxide as a hair brightening agent. Although this system successfully brightens the tone of discolored hair, hydrogen peroxide produces undesirable side effects which include a significant decrease in the tensile strength of the hair, making the hair more susceptible to chemical or combing damage, resulting in hair with a frizzy and damaged appearance, an increase in the risk of irritation or burning of the scalp or skin, an increase in risk of chemical damage to the hair upon later chemical processing, and bleaching of the natural underlying color of the pigmented hair of individuals with brown, red or black hair.
Other approaches used to brighten hair, generally natural gray or white hair, include applying a temporary or semi-permanent hair coloring, usually applied as a violet or blue rinse to mask the underlying discoloration. However, since such color rinses are typically applied and left on the hair, such rinses can produce further visually unsatisfactory tones, such as unnatural purples and blues, and can leave an undesirable dull coating on the hair.
Thus, conventional hydrogen peroxide-based brightening systems suffer from the disadvantages of reduction in tensile strength of the hair, structural damage to the hair, irritation or burning to the scalp, and color rinses unsatisfactorily color the hair.
Accordingly, there is still an ongoing need for a hair brightening composition that overcomes hair discoloration problems resulting from the use of alkaline chemical processing products or environmental exposures, which minimizes apparent damage to the hair and minimizes loss of tensile strength of the hair. There is also a need and desire for easy-to-use improved compositions which brighten the hair that can be employed during waving or relaxing hair processes which brighten the hair.
The inventive hair brightening system answers that need. Further the inventive hair brightening system and methods for brightening hair can be used as an adjunct to an alkali relaxing process.